Structural transition of copper nanowires confined in single-walled carbon nanotubes

Structural transition of Cu-nanowires confined in single-walled carbon nanotubes (SWNTs) was investigated using classical molecular dynamics simulations. The nanowires were assumed to have an fee structure with axis in the (100) direction before being encapsulated into the SWNTs. With increasing temperature, the initial fee structure of the confined nanowires was found to transform into a coaxial cylindrical multi-shell structure within the SWNTs. Due to larger thermal expansion coefficient of the Cu-nanowire, the confining pressure inside SWNT increases with rising temperature. The combined effect of pressure and the cylindrical geometry of SWNTs are believed to play a dominant role in the structural transformation of the encapsulated Cu-nanowires. The transition temperature of the nanowire under conditions of varying degrees of confining pressure and geometry templating was investigated.